1. Field of the Invention
The present invention relates to a digital video disc player and, more particularly, to a digital video disc player which is operable to simultaneously produce more than one picture from a digital video disc on which multiple pictures are recorded.
2. Description of the Related Art
In digital video discs, picture information produced by coding photographed pictures at- various angles is recorded so that users can display or reproduce pictures in vivid detail. A digital video disc player reads and reproduces picture information previously recorded on a digital video disc. FIG. 1 shows a block diagram of a conventional digital video disc player. Referring to FIG. 1, a controller 10, which can take the form of a microcomputer, controls a servo controller 14 and data controller 20 according to signals from a user interface 12. Controller 10 displays a menu by which users can control various functions of the video disc player and make picture selections using interface 120 The selected picture signals are provided on an output device 32. Here, the user can select a picture photographed at a predetermined angle from those pictures recorded at various angles onto the disc.
Servo controller 14 receives optical pick-up driving information from controller 10, and operates an optical pick-up 160 Optical pick-up 16 reads information recorded on a digital video disc 18 under the control of servo controller 140 Digital video disc 18 contains servo information and picture information coded in moving picture experts group-2 (MPEG-2) format. The servo information includes information indicating where the picture information is recorded on the disc.
Servo controller 14 reads selected picture location information and operates optical pick-up 16 to transmit picture location information to controller 10. Controller 10 sends the picture location information to data controller 20, and transmits instructions for reading the picture location information to servo controller 14. Optical pick-up 16 reads the picture information from digital video disc 18 under the control of servo controller 14 in accordance with the reading instruction The coded picture information is sent to data controller 20.
Data controller 20 transfers the coded picture information to a video decoding portion 26 when the picture location information of controller 10 corresponds to the recording location of the picture from optical pick-up 16. Video decoding portion 26 consists of an input buffer 22 and a video decoder 24, which uses conventional techniques we to decode data stored in MPEG-2 format Input buffer 22 buffers the picture information while the buffered picture information is being sent to video decoder 24. Video decoder 24 reproduces the buffered picture information, and the reproduced picture information is transmitted to a reproduction picture buffer 28. Reproduction picture buffer 28 buffers the reproduced picture information, which is then fed to an output controller 30. Output controller 30 converts the reproduced picture information into an analog picture signal, that is then reproduced by output device 32 as a picture. The output device 32 conventionally is a television set.
FIG. 2 shows a process of reproducing a picture with the aforementioned conventional digital video disc player. Referring to FIGS. 1 and 2, the user selects a predetermined picture from pictures stored at various angles on digital video disc 180 The picture selection is performed through user interface 12. The selected picture is referred to as a first picture for convenience When the first picture is selected through user interface 12, controller 10 performs a step 34. At this step, controller 10 receives picture selection information corresponding to the selection of the first picture through interface 12. When step 34 is completed, controller 10 performs a step 36. At this step, controller 10 reads picture location information indicating where the coded first picture is recorded on digital video disc 18.
Next, the structure of data recorded on digital video disc 18 will be described with reference to FIG. 3 showing the recording format of digital video disc 18. The picture location information section consists of a first picture information block, second picture information block, third picture information block, . . . , and continues through the Nth picture information block. As shown in FIG. 3, if the first picture information is recorded in a sector L, information regarding sector L is stored in the picture location section corresponding to the first picture. If the second picture information is recorded in a sector M, sector M is recorded in the second picture location information section. Furthermore, If the third picture information is recorded in a sector N, sector N is recorded in the third picture location information section.
In order to determine the location of the first picture information, controller 10 generates an optical pick-up driving control signal for servo controller 14, which instructs servo controller 14 to read the first picture location information section. Servo controller 14 controls optical pick-up 16 according to the optical pick-up driving control signal. Optical pick-up 16 reads the location for the first picture location information section under the control of servo controller 14. The read first picture location information is sent to controller 10.
Then, controller performs a step 38. At this step, controller 10 sends the optical pick-up driving control signal to servo controller 14 according to the first picture location information Servo controller 14 controls optical pick-up 16 according to the optical pick-up driving control signal Optical pick-up 16 reads the location where the first picture information is recorded, that is, reads the picture information recorded in sector L under the control of servo controller 14. The read first picture information is sent to data controller 20. When the read operation of optical pick-up 16 is completed, controller 10 performs a step 40. At this step, controller 10 sends the first picture location information to data controller 20. That is, information about sector L is sent to data controller 20. By doing so, the operation of the controller is accomplished.
If the recording location of the first picture information obtained by optical pick-up 16 corresponds to the first picture location information from controller 10, data controller 20 transmits the first picture recording location information to video decoder 26. If not, data controller 20 ignores it. Picture information sent to video decoder 26 is reproduced as a picture which is displayed by output device 32, after passing through reproduction picture buffer 28 and output controller 30.
With the above-described conventional video disc player, the user cannot display a first and second picture simultaneously. This is because a conventional digital video disc player can process information of only a single picture at a time. Accordingly, the user cannot watch multiple pictures simultaneously.